Heater blower mode? - why break as soon as it gets cold???

[langb20]

Hi all,
Typically as the cold weather has returned my heater blower snuffed it
Van was stood a while, and surprisingly the heater blower worked initially (I know, not siezed! wow - I have replaced one before and not looking forward to taking the dash out)

So to the symptoms: speed 1 worked fine, 2 also, even 3, little bit of a squeek but nothing major. I left it on 1 by mistake - I think it's a mistake in hindsight anyway, because I then drove around for a bit, smelt a bit of electrical smoke and switched the fan off right away. I've had this happen before, again with a blower that was from a van that had been standing, did all the painful bit of dash out and replaced (with a bit of lube for longevity) then hit the road with the fan on - have to try it out right?! then the all too familiar electrical smoke smell, burnt dust even. grrr, once I'd say is bad luck but twice? something is going on here.

Question:
Should the normal mode for the fan switch be zero when driving? since the natural draught is quite impressive on it's own (when driving >30mph). My theory here is that if the speed setting is on 1 say, but the natural draught of air pushing through the heater system at 30-50mph is 'quicker' than the fan speed, it's effectively over-speeding the fan and burning out the motor contacts? am i way off here?

So i'm left now with a blower that does naff all on speeds 1 & 2, and dims the lights on 3 - I don't leave it on 3 for long for obvious reasons, must be a lot of power draw but i've not got the multimeter out yet. No fan noise/flow on any speed. It's still able to spin in there as the natural draft when driving is providing heat in all the right places (had a siezed one in another van one time and the flow is quite reduced when siezed). I'm hoping the switch or resistor connector is at fault, but still may be dash-out job

Anyone experienced something similar? any insights appreciated
Brent

[CovKid]

Well, the fan actually runs flat out by default and its only a series of resistors that reduce the speed. The only sure fix is a new fan and associated switch (if required). The motor starts to break down internally leading to bearing failure or gradual shorting. You can sometimes extend life of a seized one by lubing them but eventually they give up through sheer old age. Motor not expensive but pain to get at. On vans made before 85 both wipers and blower are on ONE fuse. I added a mod for that in WIKI so you don't lose both in the event of a failure in either motor.

Like all old electrical items though, a drop in temperature can be enough to finish them off.

[HarryMann]

but the natural draught of air pushing through the heater system at 30-50mph is 'quicker' than the fan speed, it's effectively over-speeding the fan and burning out the motor contacts? am i way off here?

Yes you are I think.

I've been using draught only on one of mine almost since I bought, bit annoying on a really wet damp da, but once moving soon demists, diesel so heats up very quickly too... will get a round tuit one day

Maybe its the damp as much as the cold or the combination, as Ralph says, many lecy probs develop as soon as temp drops below say 5 degrees C.

[Red Westie]

I found that in addition to the blower motor any repair needs to include switch and sometimes teminal relacement. Typically the brass contacts of the switch and spade connections become heavily tarnished increasing resistance with the result of melting wires and blower switch.

Martin

[langb20]

Thanks for the replies, as i feared then - i'll pick a day to take it all apart, trouble is i know there are loads of other things to do 'while i'm there' namely the bottom window corner leak. hmmm
just put an AAZ in and yes it heats up quite nicely so no problem when i'm driving, but soon the windscreen won't be just misty from standstill, it'll be frozen
It's an '85 van too with early fuses so likely single fused for wipers and blower then, thanks for that i'll do the mod 'while i'm there' this list is going to get longer me thinks!
Anyone know where's best to get a replacement blower from, think i saw some for £40 on ebay ages ago, not sure of quality mind.
Thanks again

[1664]

Brickwerks do one http://www.brickwerks.co.uk/shop?page=s ... gory_id=55" onclick="window.open(this.href);return false;

does the resistors too http://www.brickwerks.co.uk/shop?page=s ... gory_id=55" onclick="window.open(this.href);return false;

[CovKid]

I don't think they're that expensive through GSF either if I remember rightly although that motor fits several VW models. Not sure you'll fix bottom corner leak without lifting out windscreen - see https://club8090.co.uk/wiki/Bo ... well_leaks" onclick="window.open(this.href);return false;

If you do have problems up front, best do them in one go as you'll have a nice warm dry cab for the winter then.

[HarryMann]

Just put an AAZ in and yes it heats up quite nicely so no problem when i'm driving, but soon the windscreen won't be just misty from standstill, it'll be frozen

Not saying don't delay, but used mine during that anow & freeze early this year without, but not as a daily driver! Park facing the South if you can

[langb20]

Hey thanks for the links there, very handy. unfortunate that it's my daily drive there as i'll need to get it done quickly, screen has a 1"chip/crack 4" from the bottom and 6" from O/S, so i'm half certain it'll fully crack when I take the bugger out. One thing after another it seems
i'll glass fibre the 1/4" hole above the o/s wiper after I get the blower fixed I think, next spring i'll sort the gutter
can't fault brickwerks with their quality gear